706 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 



Platycrinus pocilliformis Hall. 

 Plate LXVIII. Figs, ^a, b. 



1858. Hall; Geol. Rep. Iowa, Vol. I., Part II., p. 528, Plate 8, Figs. 2a, 6. 



1881. W. aud Sp.; Revision, Part II., p. 74 (Proceed. Acad. Nat. Sci. Pliila., p. 248). 



A little shorter than the preceding species. Calyx to the top of the 

 radials cup-shaped, wider than high ; the height of the basals equal to nearly 

 one third the length of the cup ; the sides very slightly expauding to the 

 middle, the upper ends at right angles to the base of the cup ; the suture 

 lines not grooved. Surface of plates marked by rather short, rounded 

 nodes, which upon the basals are arranged in double or triple rows, a row 

 of three extending from the column facet to the upper angles. The radials 

 generally have a row of four or five nodes running from the radial facet 

 to the lower angles of the plates, which enclose four or five others, and there 

 are three or four at each side. 



Basals forming a flat, pentagonal cup ; the column facet small and barely 

 impressed ; the interbasal suture lines indistinguishable. Radials a little 

 wider than long, quadrangular, the upper face constituting an almost 

 straight line ; facets small, directed obliquely upwai'd, restricted to the 

 upper ends of the plates, and occupying but one third their width. 

 Anns apparently five to the ray, and ornamented with small nodes. 



Horizon and Locality. — Lower Burlington limestone, Burlington, Iowa. 



T//23e in the (Worthen) Illinois State collection, Springfield. 



Remarks. — Differing from P. verrucosus in the shorter calyx, in having 

 less prominent, and differently arranged nodes, and in the ornamentation of 

 the arms. 



Platycrinus Yandelli 0. and Sh. (typical form). 



Plate LXVI. Figs. 6a, h, c; and Plate LXVIII. Figs. 3a, h, c. 



1832. Owen and Shumakd ; XJ. S. Geol. Rep. Wise, Iowa and Minn., p. 5S7, Plate 5 J, Figs. 6«, b, c. 

 1881. W. and Sp. ; Revision Pateocr., Part II., p. 76 (Proceed. Acad. Nat. Sci. Pbila., p. 250). 



Of medium size. Dorsal cup low cup-shaped, obscurely pentangular from 

 a dorsal view, the interradial suture lines forming the angles ; the sides 

 nearly straight, slightly expanding. The radial facets almost in the same 

 plane with the surface of the plates, and unusually large, occupying fully 

 half the length of the plates and two thirds their width. Surface of basals 



